The least complicated method for the removal of stones from the bile duct at present consists of the endoscopic splitting of the papilla and subsequent extraction of the stone.
For this purpose a perorally introduced lateral-viewing duodenoscope is used, after passage through the esophagus and the stomach, to locate the discharge branch of the duodenum, where the bile duct and the pancreatic duct have a common opening in a wart-shaped protrusion (papilla).
The opening of the papilla is first intubated with a probe pushed laterally out of the duodenoscope. by means of a contrast medium injected with the probe the two ducts are made visible radiologically, when the stones show up as spaces in the contrast medium. After the stones have been revealed in this way the probe is removed and in its place a so-called papillotome is introduced into the bile duct--likewise through the duodenoscope--so that the section of the papillotome that can be curved by means of the traction wire is in the region of the papilla. By traction on the traction wire at its outer end, whereby the papillotome is caused to curve and the traction wire is stretched as a chord, and by simultaneously connecting the traction wire to a source of current, the papilla is cut in conformity with the upwardly extending bile duct. The stone can then spontaneously emerge through the widened papilla, or be withdrawn with an instrument (a collecting basket).
Because of physical conditions the chord of an arc formed by the traction wire after the traction always faces upward, i.e. approximately along the line of the duodenoscope. The direction of the cut is thus substantially predetermined, and in practice it is not possible, if so desired, to make a lateral cut without changing the position of the duodenoscope, which would require the duodenoscope to be re-oriented. This state of affairs is of considerable importance, since the cut in the papilla must always correspond to the course of the upwardly extending bile duct or of the bulge adjoining the papilla. A cut laterally across this bulge would be a serious complication because of perforation, with possibly fatal results.
With this known design both the introduction of the probe described above and the cutting open of the papilla by means of the papillotome corresponding to the upward course of the bile duct are difficult, since the direction of curvature of the probe or of the papillotome depends solely on the force of traction, but is not fixed, so that substantial deviations can occur.